With the exception of quarterback, cornerback might be the most difficult position in sports. It's also one of the toughest to project when evaluating young players. The physical tools and mental toughness and confidence it takes to be productive week in and week out often are underrated by outsiders looking in.
The demand for this position in terms of size has changed somewhat over the past few years with the influx of bigger wide receivers seeming to dominate the college game today. Size is becoming more of a factor, especially in the red zone, because big wide receivers will take advantage of short defensive corners, and although coverage might be good, the wide receivers will outjump those corners at the goal line.